Blasting cartridge



Aug; 18, 1931.l F. H. KNEEL-AND '1,818,993

- BLASTING CARTRIDGE Filed Nov. 27, 1929v @N mwNNkNf Q1 HMIIIII named Aug. is, 1931 UNITED STATES PATENT OFFICE RANK H. INEELAND, l' CHICAGO, ILLINOIS, ASSIGNB T0 BAFFIY IINING OOI- PANY, 0I CHICAGO, ILLINOIS, A CORPORATION nusrmo omarmen Application med November 8?, 1988. Serial No. 410,196.

This invention is concerned with blastin cartridges ofthe type wherein a com resse gas is employed as the blasting medium.

It is an ob]ect of the invention to simplify l and thereby reduce the cost of construction and maintenance of blasting cartridges of the character indicated.

More particularl it is an object of the invention to provi e an improved and simplified means for the charging of such blast- 1n cartridges.

ferring to the drawings,

Figure 1 is a view in longitudinal section illustrating an embodiment of the invention.

Figures 2 and 3 are enlarged fragmentary sectional views showing the two operative positions of the chargin device.

The cartridge with which the present invention is associated consists generally of a 80 cylindrical casing 1 which is internally hollowed out to rovide a chamber 2, the open end of w ich is designed to be covered and sealed by a rupturable discharge disc 3. Secured adjacent the discharge disc 3 is a ring 4 formed of relatively hard steel, the function of which is to serve as ananvil or shear ring for the mild steel disc 3.A This shear rin is forced into tight engagement with the isc 3 by means of a dischar ca 5, having threaded enga ment with t e en pf the cartridge body. The chamber ad- ]acent the opposite end of t cartrid is tapered toward the axial center line o the cartridge and at the center is bored out to receive an electrode 7, which extends a short distance into the gas chamber. The electrode is insulated from the body of the cartridge by means of an insulating member 8. The electrode 7 is formed as a rtion of an enlarged sealing head 10 whi is insulated from the body of the casing by means of anl insulating disc 11. The disc 11 also serves the urpose of providing a seal between the matze r 0 and the attllljlacetilllt wall of theta cartri t us reven e -esca o Y from the cham r 2 arond the elecpti'ode. gaAs retainin vand protecting disc 12 is screw thread and bears against the outer surface of the imv member 10. This disc is adapted to be linto the end of the cartridge body screwed tightly in place by means of a pin wrench or the ike, t us exerting pressure on the member 10 and eiecting a secure seal between t-he member 10 and the cartridge body. It will be noted that member 10 and protector disc 12 are also separated by insulating member 13.

The cartridge as above described is designed to be charged with a compressed as, the pressure of which may be lncrease to effect rupture of the disc 3 by means of a heater unit 18. This heater unit extends between and has electrical contact at its op osite ends with electrode 7 and ruptura le disc 3 respectively and is of such construction as to be res onsive to the passage of a relatively low e ectric current. In order to pass a suitable current through the heater unit, it is merelg7 necessary to insert a contact plug through t 12 and into the bore 16 provided therefor in the electrode. The other lead from a source of electricity may be connected directly to the bod of the cartridge referably by means o a wire passed throng one or more apertures 17 formed therein. In the interest of safety, the o eningb14 in the protector disc is normally c osed y a pivoted cover plate 15thus preventin the accidental engagement of the electro e with a source of electricity.

The present invention is more particularly concerned with the method and means whereby cartrid of this character may be charged wit a compressed or liquefied s. As herein shown this result is accomplis ed i without the addition of a se arate valve unit.

Referrin particularly to igures 2 and 3 it will be o served that there is positioned bee opening 14 in the protector disc tween the ru turable disc 3 and the cartridge,

a ket 19 ormed of fibre or any other suitab e deformable material. It will also be 'noted that the sealing surface of the car tridge with which the disc 3 and the gasket 19 are designed to cooperate, is of stepped 1 engagement with t e step 20 of the sealing i surface formed on the cartridge. With the parts in this relative position, gas may be introduced by means of a suitable charging nozzle through the nozzle seat 23 and charging port 22, directly into the gas chamber 2. This is possible due to the fact that the gasket 19 is not in sealing engagement with the step 21 of the sealing surface. After the desired amount of gas has been charged into the cartridge, the discharge ca p ma be screwed further into the cartridge body, thus exerting an additional pressure on the disc 3 and gasket 19 and causing the gasket to be deformed in such a way as to effectively seal the entire area of the sealing surface formed on the cartridge and including both the steps 2O and 21. It will be apparent that after this has been done, the gas chamber is completely sealed against the escape of gas either around the discharge disc and through the discharge cap or through the charging orifice 22. It is guite well knownthat it is possible to cause bre or the like to flow when subjected to high pressures and this is substantially what occurs when the discharge cap is screwed very tightly into the cartridge body. The gasket not only conforms to the two steps of the sealing surface formed in the cartridge, but also flows into the charging orifice 22 and effectively seals the same.

In view of the foregoing it will be appreciated that the present invention provides for the effective and eicient charging of blasting cartridgeswithout provision of a separate valve unit for this purpose. Thus, the construction of cartridges is rendered less :ostly and their operation and maintenance is simplified. It is to be understood that the elements which herein serve the purposes of a valve are elements which are normally essential to the operation of this type of :artridge even though a separate valve be `orovided. It should also be understood that he deformable gasket is not an additional aart peculiar to the present construction but s one which is normally used in cartridge :onstruetion prior to the present device. In aractice, it has usually been necessary to )rovide a new gasket each time a cartridge .s recharged and this of course holds true with the present construction.

I claim:

1. A blasting cartridge comprising a rigid :asing having an opening therein, stepped iealing surfaces surrounding said opening, a :losure for said opening, a gasket interposed ietween said closure and said stepped surfaces, means for forcing said closure and gasket toward said stepped surfaces to successively seal the closure on the respective suraces and a passage for introducing gas into yhe cartridge beneath the closure when the :lesure is sealed against the first of said tepped surfaces, said closure and gasket servrigid closure for said opening, a deformable gasket interposed between said closure and said sealmg surfaces, a charging port leading from the second of sa1d sealing surfaces to the exterior of the casing, and means for forcing said closure and gasket toward said stepped surfaces to successively seal thereon.

3. A blasting cartridgeV comprising a rigid casing having a discharge opening therein, stepped sealing surfaces surrounding said opening, a rupturable disc adapted to close said opening, a deformable gasket interposed between said disc and said stepped surfaces, a charging passage leading from one of said stepped surfaces to the exterior of said casing and means fol` forcing said disc and gasket toward said stepped surfaces to successively seal thereon, said charging passage being in communication with the interiorof said casing when said disc and gasket are sealed on one of said surfaces and being effectively obstructed and out of communication with the interior of said casing when said gasketis deformed to seal on another of said surfaces.

il. A blasting cartridge comprising a rigid eas-ing having a discharge opening therein, a closure for said opening, means for exerting pressure on said closure to effect an initial sealed relation between the same and said cas-v ing, a gas passage having communication with the interior of said casing when the closure is so sealed, said closure being movable in response to additional pressure exerted thereon by said means to seal said gas passage as well as said opening.

5. A rigid casing having an opening sur roundedby stepped sealing surfaces, a closure, a deformable gasketinterposed between said closure and said sealing surfaces and adapted to successively engage said surfaces in response to pressure exerted thereon by said'closure, said casing having a fluid -passage extending from one of said' stepped surfaces to the exterior thereof and means associated with saidcasing for exerting pressure on said closure.

Signed at Chicago, Illinois this 19th day of November, 1929.

FRANK H. KNEELAND. 

